DESCRIPTION (Applicant's Abstract): People with serious mental illness (SMI) have been shown to be at elevated risk for HIV infection, yet little is known about SMI HIV-positive persons, and virtually nothing about the HIV care they are (or are not) receiving. The broad goal of this 4-year study is to provide an understanding of this population and how the current system of care is responding to their needs so that care may be improved. What is known about this population and the overcrowded, underfunded systems charged with their care suggests that SMI persons are likely to be diagnosed at later stages of HIV infection, and have more precipitous illness courses and shorter survival times. This study will make use of data and methodology from the HIV Cost and Services Utilization Study (HCSUS), a large longitudinal study of a nationally representative sample of 3300 persons who are HIV-positive and are known to HIV providers. A random sample of 700 SMI HIV-positive adults in 8 U.S. sites will be studied and compared to non-SMI HIV-positive participants in HCSUS. The specific aims are: to describe the demographics, clinical and general health characteristics of this sample of 700 SMI HIV-positive adults; to determine their patterns of utilization and costs in order to evaluate access to care and quality of care; to compare their stage of HIV disease at entry into care and 18-month survival rates with non-SMI HIV-positive persons; and to assess organizational, financial and policy-related barriers to their receiving appropriate care. These aims will be achieved by collecting and analyzing both quantitative data (face-to-face interviews) to assess demographics, psychiatric diagnoses, HIV status, access to and utilization of services, health-related quality of life, satisfaction with HIV services, and HIV knowledge and risk behaviors; medical and billing record abstractions; and 18-month survival information and qualitative data (case studies, focus groups, and participant-observation) in all 8 sites.